一种适用于谐波起动电动机的新型定子绕组

通过对谐波起动电动机广泛采用的定子绕组存在问题的分析,提出了一种结构更加简单、控制更加方便的定子绕组,该定子绕组线圈的匝数、线规都相同,解决了谐波起动电动机定子绕组不等匝引起的设计和制造工艺困难的问题.对该绕组的设计方法进行了分析和介绍,并以8极72槽定子绕组实例加以说明.     

电机定子绕组湿裂引起电机匝间的分析

电机定子绕组匝间是指电机同一相的线圈绕组匝之间的绝缘,由于绝缘结构和绝缘材料不同以及在绕线、嵌线、刮线接头、端部整形、绝缘浸漆、装配等工序中因操作工艺不当而引起不同程度的绝缘损伤并在绕组通电后产生短路的现象。绕组匝间短路将导致定子电流急剧增大,进而烧毁电机绕组。因此必须高度重视定子绕组匝间问题,及时查找原因,采取预防措施,避免事故发生。     

Proposal and Feasibility Study of the Integrated Diode Synchronous Motor

This paper presents a new type of magnet‐free motor that has concentrated stator windings and rotor coils with a pair of diodes. The most important feature of this motor is that currents in the rotor coils can be generated by utilizing the changes in the spatial second harmonic of the magnetic fields due to the concentrated stator windings, which normally increase motor losses. A prototype of the motor was designed and fabricated, and its basic performance was evaluated. First, using simplified analytic models, we explain the mechanism of inducing currents in the rotor coils by the changes in the spatial second harmonic of the magnetic fields. Second, we compare the torque performance of the proposed motor and that of other types of motors including a magnet motor through finite‐element analyses. The analyzed data show that the proposed motor can possess greater torque/volume ratio than that of the other motors. Finally, using the measured data, we validate the mechanism of inducing currents in the rotor coils, and examine the torque and power characteristics of the motor.     

单、双层不等匝正弦绕组线模的尺寸计算

为了减少谐波磁势,削弱同步附加转矩,提高电机的效率及改善电机性能,三相异步电机的定子线圈广泛采用单、双层不等匝正弦绕组(以下简称正弦绕组)。由于正弦绕组每极每相下各线圈的跨距和导体数均不相等,其绕线模尺寸计算复杂,文章介绍了它的计算方法。     

高压交流电机定子超薄型绝缘工艺研究

通过对高压电机定子绝缘结构进行分析,以薄型云母带、少胶粉云母带绕包绕组线,构成定子线圈绝缘。定子绕组整体VPI浸渍无溶剂环氧酸酐浸渍树脂的超薄型绝缘系统,实现了高压交流电机定子绝缘的整体减薄。以6kV级电机为例,定子线圈单边主绝缘厚度由常规型的1．4mm减薄到小于1mm。     

高压电机定子采用散绕组的绝缘结构分析

高压电机的定子通常采用成型绕组,同时需配套开口槽,导致电机成本增加、气隙磁场谐波含量增大、齿槽转矩增大等一系列问题。为了解决上述问题,可以采用散嵌圆铜线绕组。对于高压电机采用散绕组,绝缘问题是关注和研究的重点。以1台高压散绕组电机为例,利用有限元法分析了高压电机采用散绕组的绝缘结构可靠性,分别分析了匝间绝缘、主绝缘、层间绝缘和端部绝缘的绝缘情况以及主绝缘被冲片毛刺划伤情况下的电场强度分布,并根据分析结果针对电机槽内绝缘做出了优化,制造了1台样机并对样机进行了耐电压试验。验证了高压电机定子采用散绕组在一定程度上是可行的,为高压电机定子绝缘结构设计提供了参考。     

多极电机有绕组定子制造工艺改进

多极电机具有槽数多、跨距短、槽满率高等特点。对此类电机而言,若采用普通三相异步电动机嵌线工艺,操作难度大,且有绕组定子铁心的故障率高。针对这一问题,介绍15 kW发电机有绕组定子制造工艺的改进方案。通过工艺改进,可以降低绕组嵌线难度和故障率,提高劳动效率。     

电机实现外装压工艺改进

介绍了YZR250-YZR355电机外装压生产的实施和改进过程。通过在生产过程中对冲片制造难点、铁心制造难点、有绕组定子铁心装压难点的解决,实现了电机外装压。使铁心压装、嵌线、浸漆与机座加工平行作业,缩短了生产周期,提高了生产效率和产品质量。并对取得的经济效益进行了分析和计算。     

转子甲类波绕组排列方法的探讨

为方便绕线型异步电动机的设计和接线操作,明确转子波绕组一端接线法十分必要。从电角度的观点出发确定三相绕组首端引出线位置。根据波绕组的连接规律进行各相带的槽号分配,进而利用Excel公式法编排绕组表。这种方法不但易于掌握,而且通过绕组表可直观的确定上下层整距、短距、引线线圈所在槽号,为绘制转子接线图和设计转子线圈奠定了基础。     

Stator‐core structure and winding technology for EPS motors

Electric power steering (EPS) motors must have the performance characteristics of precision machines. They should be compact and produce high power. Moreover, the loss torque and the change of loss torque should be as low as possible. In this study, dividing the stator core into small blocks and winding the coils densely on the blocks are shown to be effective techniques for achieving compact high‐power motors. We examined whether I‐shaped divided cores or T‐shaped divided cores were more suitable for EPS motors in terms of motor performance and production cost. We built two experimental motors, one with I‐shaped divided cores and the other with T‐shaped divided cores, and measured three important characteristics of EPS motors: output torque, loss torque, and loss torque change. The T‐type motor proved to have better performance for all three characteristics. Moreover, the productivity of the T‐type motor was shown to be higher than that of the I‐type motor, indicating that overall, T‐shaped divided cores are advantageous for the stators of EPS motors. Next, we considered a new winding method for the continuous winding of two T‐shaped cores in order to achieve a compact terminal connection board. The extending lines made by the new winding method do not extend beyond the coil end. Therefore, this method will contribute to reduction of the axial dimension of EPS motors. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 35–42, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21085     

The temperature effect on the performance of a traction asynchronous motor

The faults and damages of the asynchronous motors currently used in the traction rolling stock are reviewed. It is shown that a significant number of failures in operation are due to the excessive temperature in the stator coil and how it affects the mechanical characteristics and the traction performance of the asynchronous motor windings.     

Analysis and characteristics of a permanent magnet-type bearingless motor

Super-high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high-power drives can be achieved with bearingless motors. In this paper, a bearingless motor with principles of permanent magnet-type synchronous motors is proposed. High-power factor and high efficiency can be expected in permanent magnet-type bearingless motors. The proposed bearingless motor is a 4-pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. The relationships between radial forces and the permanent magnet thickness were derived. From these relationships, the optimal permanent magnet thickness to produce radial forces efficiently is found. A test machine was built to confirm the relationships of radial forces, currents and voltages.     

基于Solid Works的电机定子成型线圈参数化设计

大中型电机定子线圈一般采用成型绕组作为电机的核心部件。因此,成型绕组的设计和制造对整个电机性能参数起着关键作用。利用三维设计软件SolidWorks,基于经典定子硬线圈作图法,并结合实际涨形机参数特点,给出了定子成型线圈参数化设计方法,实现三维模型的快速修改与重建,显著提高了设计效率与设计精度。     

散线同心式绕组制造工艺

低压大功率电机散嵌绕组由于并绕根数多、线圈截面较大、绕组端部较厚,整型成为绕组制造过程的难点.同心式绕组嵌线方便,端部整型容易,解决了散嵌绕组嵌线过程整型难的问题.并从同心式绕组制造工艺进行分析,从中归纳总结了同心式散嵌绕组的制造经验,为制造类似电机提供了一定的参考.     

Detection of stator short circuit faults in three-phase induction motors using motor current zero crossing instants

Stator faults typically have a significant share amongst the common type of faults in industrial three-phase induction (asynchronous) motors. This paper presents a motor current signature analysis (MCSA)-based diagnostics of the stator winding short circuit fault. This type of fault happens due to the destruction of the turn insulation, and can be very detrimental causing motor shutdown. Instead of traditional MCSA using the motor stator current, in this paper, analysis using the zero crossing time (ZCT) signal of the stator current is presented. The theoretical aspects of the stator short circuit detection are presented. Following that, a diagnostic algorithm utilizing the ZCT signals is proposed. Experiments are performed with real motors, healthy and with shorted stator windings. Frequency analysis of the ZCT signals from the experimental data substantiates the theoretical arguments with significant accuracy.     

不同绕组连接方式下的六相永磁同步电动机MT容错控制

多自由度使多相电机具备了优异的容错能力。本文针对单中性点、双中性点及开端绕组结构的六相永磁同步电机,以缺相容错运行时输出转矩最大为目标,提出一种适用于不同绕组结构电机的容错电流计算通用表达式。通过对六相永磁同步电机缺一相故障状态下的自由度进行分析,计算了不同定子绕组结构下的容错电流,并给出相应的控制方法。对比三种不同绕组结构电机容错运行时的带载能力,开端绕组结构的六相永磁同步电机缺相容错运行时输出转矩最大。利用Matlab/Simulink建立了六相永磁同步电机模型及其控制系统,验证了计算结果的有效性。     

Diagnosis of Short‐Circuit Faults in Stator Winding Inside Low‐Voltage Induction Motor Using Impulse Voltage Test

Short‐circuit faults in windings due to the deterioration of insulation is among the most common faults in motor drive systems. An easy and effective fault diagnosis method is urgently required to ensure highly reliable operation. This paper proposes a novel method for the diagnosis of short‐circuit faults in stator winding inside a low‐voltage induction motor without removing the rotor, by performing an impulse voltage test. As the rotor does not need to be removed from the motor in this novel diagnosis method, the method can be put to practical use. In this study, first, several impulse voltage tests are carried out on the stator windings of motors. Second, the values of two features that represent the characteristics corresponding to the condition of the motor are calculated, and it is found that the shape of the feature distribution does not depend on the rotor position but on the condition of the winding. Third, the distance between the feature distribution for the healthy motor and features obtained from a target motor is calculated. On the basis of this distance, the condition of the stator winding inside the induction motor is determined. The effectiveness of the proposed diagnosis method is verified by performing experiments that involve several motors with healthy and faulty windings.     

Characteristics of a permanent magnet type bearingless motor

Super high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high power drives can be achieved with bearingless motors. In this paper, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed. High power factor and high efficiency can be expected in permanent magnet type bearingless motors. The proposed bearingless motor is a 4 pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. It was found that radial forces are efficiently produced by employing thin permanent magnets on the surface of rotor iron core. A test machine was built in order to measure inductance functions as well as relationships between voltages and currents     

New Hybrid‐Excited Motor Using Armature Windings as Field Flux Source

In this paper, a new hybrid‐excited motor is proposed. Its unique feature is that it has no field exciting coil, despite being a type of bypass yoke core (BYC) hybrid‐excited synchronous motor. Based on finite element analysis (FEA), the following facts are clarified. Since the stator coil magnetomotive force (MMF) and claw poles rotate at the same speed and in the same direction, they are motionless relative to each other. Since the claw poles are located at one of its ends near the BYC surface with a gap, it receives immovable magnetization by the stator coil MMF through the BYC; then the claw poles can supply a magnetic field flux via the BYC. This flux via the BYC increases the total torque, because its torque is added the two other torque components: the permanent magnet torque and claw poles reluctance torque. In addition, the magnetic polarity and the amount of the flux of the claw poles can be varied by controlling the armature current phase angle.     

单双层绕组在小型三相异步电动机设计中的应用

通过对电机采用单层绕组与单双层绕组进行比较,论述了电机采用单双层绕组后,可有效的提高电机效率、降低电机杂散损耗、提高电机的起动性能、降低温升,是切实可行的有效措施。